Punch holder with replaceable radius tips

ABSTRACT

A press brake system that utilizes a punch holder adapted to be used with punch chips of various radii to achieve the desired bend on a part. The system maintains a common shut height enabling the press brake operator to be able to put different radius tip punches next to each other in a single press brake tooling setup.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to an improved punch bending system.

2. Description of the Prior Art

A press brake tool typically includes a punch and a die that defines a groove to receive a punch.

Examples of prior art patents that relate to press brake tools are as follows:

1. U.S. Pat. No. 7,584,640 to Yi-Hua Liu et al, issued on Sep. 8, 2009 describes a press brake tool for bending a workpiece and includes a punch having a punch tip, a press brake die and a die holder fixing the die thereto. The press brake die includes a pair or rotary members and at least one elastic member. The press brake die further defines an elongated lateral groove facing the punch tip and at least one longitudinal through hole communicating with the lateral groove. The pair of rotary members is spaced from each other and rotatably received in the elongated lateral groove.

2. U.S. Pat. No. 6,539,763 to Chebbi, issued on Apr. 1, 2003, describes a control device for a bending machine including apparatus for inputting, as input data, a desired bend angle and bending conditions or criteria, means for storing groups of data, each containing bending conditions, a bend angle and a penetration depth, and means for searching whether the input data is stored in the memory means, in the same group of data. Moreover, means are provided for transmitting a signal representative of a penetration depth included in the group of data stored in the memory means, or for transmitting a signal for controlling the bending machine according to this penetration depth.

The aforementioned patents have at least one component in common; the punch used to bend the workpiece has a fixed radius and typically a single punch is used for each bend, a different punch being required for a different bend. In essence, manual press brake setups normally requires the machine operator to use multiple/different machine tool setups in order to complete all the bends on certain parts. This, in turn, increases the amount of setup time required thus decreasing part bending efficiency, increasing the part fabrication costs which, in turn, increases customer cost.

What is thus desired is to provide a press brake tooling operator the ability to perform many different types of bends in one machine setup thus lowering the fabrication cost of a part.

SUMMARY OF THE INVENTION

The replaceable radius tips of the present invention are designed to be removed from the radius tip punch holder, but still maintain “common shut height” properties. No matter what different radius tip is used, the punch tips bottoms out equally into the common shut height dies. This allows the press brake operator to be able to put different radius tip punches next to each other in a single press brake tooling setup.

The newly designed punch bending system uses a common punch holder and offers various replacement punch chips to achieve the desired radius on a part that is being bent on a press brake. Regardless of the radius punch bolted to end of the punch holder, a unified common tool shut height is maintained. This allows the press brake operator to achieve a unified machine shut height using multiple different radii in one press brake setup alongside other common shut height tooling without the need for manually added shims to get proper common bending height.

This stage bending system of the present invention provides the press brake tooling operator the ability to do different types of bends in one machine setup, thus greatly reducing the amount of setup time and increasing part bending efficiently, thus lowering the cost of the fabricated part.

DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention as well as other objects and further features thereof, reference is made to the following description which is to be read in conjunction with the accompanying drawing therein:

FIG. 1 illustrates a simplified version of a press brake machine illustrating the shut height measurement;

FIG. 2 illustrates the press brake tooling in accordance with the teachings of the present invention;

FIGS. 3A-3B illustrates how different radius tips can be used in conjunction with the press brake tooling shown in FIG. 2; and

FIG. 4A illustrates a partial front view of the press brake showing the tooling extending along the horizontal axis of the machine and FIG. 4B is a side view along lines 4-1, 4-2, 4-3 and 4-4 of FIG. 4A, respectively.

DESCRIPTION OF THE INVENTION

The present invention provides a punch holder having replaceable radius tips. The replaceable radius tips can be removed from the universal radius tip punch holder, but still maintain a common shut height. No matter what different radius tip is used, the punch tips bottoms out equally into the common shut height dies. This allows the press brake operator to be able to put different radius tip punches along a horizontal axis next to each other in a single press brake tooling setup.

The punch bending system of the present invention uses a common punch holder and offers various replacement punch chips to achieve the desired radius on a part that is being bent on a press brake. Regardless of the radius punch bolted to end of the punch holder, a unified common tool shut height is maintained. This allows the press brake operator/user to achieve a unified machine shut height using multiple different radii in a single press brake setup which enables the user to stage multiple part bends in one machine setup. The stage bending replacement chip tooling of the invention can be setup in a press brake machine alongside other common shut height tooling without the need to manually shim it up to provide a common bending height.

As noted hereinabove, manual press brake setup normally requires the operator to use multiple/different machine tool setups in order to complete all the bends required on certain parts. The stage bending system of the present invention allows the press brake tooling operator the ability to do many different types of bends in one machine setup greatly reducing the amount of setup time and increasing part bending efficiency, lowering the cost of the part being fabricated and, as a result, saving customer money.

The tooling system of the present invention allows all punches to penetrate to the bottom of the V opening on the dies equally, but the overall die heights at the top of the V may vary in overall size. This requires the press brake machine backgauge to be able to move up or down from one die to the other die in order to properly gauge the part over the die when bending.

The “shut height” as used in conjunction with brake presses is typically defined as the distance between the die and the anvil at the end of the working stroke.

As will be set forth hereinafter, a plurality of interchangeable radius tips (tools) are fastened to a universal holder by a plurality of bolts.

Common shut height radius chip type tools have a common/unified shut height to allow for staged bending with other common shut height tooling that have the same common/unified shut height without the necessity of shimming. Common shut height radius chips are used interchangeably in a common shut height set-up wherein the shut height remains the same.

In a simplified representation of a press machine 8 illustrated in FIG. 1, there is a maximum height of the die that can be installed. If the maximum height is exceeded, it is not possible to install the die in the press machine. There are two methods of expressing this height, namely, die height and shut height.

Referring to FIG. 1, when the punch slide 10 is at the bottom dead center position and the slide adjustment screw 12 has been raised to the topmost position, the distance from the bottom surface of the slide to the surface of the bolster plate 14 is called the “die height”, a distance represented by the reference letter A. When the bolster plate 14 is removed from the press machine, the surface on which the bolster plate was is called the “head surface”, and the “shut height”, represented by the reference letter B, is the distance from this head surface to the bottom surface of the slide.

When a die lower than the maximum adjustable height is installed, it is easily installed if the die height is within the adjustment range of the slide adjustment screw. In the case of a die with a height smaller than the adjustment range of the slide adjustment screw the height is adjusted using spacers or shims. The work of installing a die in the press machine is called “die setting up”, and the height adjustment is a significant factor that affects the time taken for this die setting up.

Bolster plate (or bed) 14 is a large block of metal upon which the bottom portion of a die is clamped; the bolster place is stationary. The slide 10 is also a solid piece of metal that is clamped to the top portion of a stamping die and provides the stroke (up and down movement) that causes the die to produce parts from the metal being fed through it.

FIG. 2 illustrates the press brake tooling 20 of the present invention which can be adapted for use in commercially available press brake devices.

Tooling 20 comprises punch holder 22, punch chip 24 and four draw bolts 26. Punch holder 22 is attached to punch chip 24 by aligning bolts 26, which pass through holes 28, with holes 30 formed in punch chip 24.

FIG. 3A illustrates punch chips having different radii (from left to right, 10 mm, 8 mm, 6 mm, 5 mm, 4 mm and 3 mm). The radius tips 24 are interchangeable and are fastened to holder 22 by draw bolts 26 (FIG. 2).

Punch holder 22 is structured to be universal in the sense that the upper portion 32 has a common design so that it easily attaches to the corresponding structure in the press brake apparatus.

Common shut height radius chip type tools have a common/unified shut height B to allow for stage bending with other common shut height tooling that have this same common/unified shut height; this enables common shut height radius chip type tooling can be used for staged bending alongside other common shut height style tooling without shimming.

Common shut height radius chips can be used interchangeably in a common shut height set-up and shut height will remain the same as shown in FIG. 3B.

The operator set up procedure is as follows:

Operators set up different lengths of tooling including different replacement radius tip punches and common shut height dies and other common shut height tooling punches in a single set-up. The common shut height dies 25 can vary in V-opening width and angle. Also, different radii for replaceable radius tip punches can be set up alongside each other.

This setup of different radii for replaceable radius tip punches, common shut height dies, and other common shut height tooling is designed to be able to process a part or multiple parts in a single set-up without having to remove or add any tools.

The operator sets the punches and dies in the brake system. The longitudinal position of the tooling is based on factors such as product shape, length and material thickness. The setup also varies based on application requirements. The number of individual setups (single mating punch and die) that comprise the entire setup along the entire length of the brake also varies by part.

The ram of the brake is lowered by the operator to bend a part that is held into position by a back gauge (not shown). The ram lowers with the tool setups and is able to bend a single bend on the part on the individual setup that the back gage supports at this time. After the bend in the part is fully processed, the ram retracts to an open position and the operator removes the part from this individual setup.

Next, the back gage moves to support the part at a different tool setup and the process of lowering the ram, bending and retracting is repeated. This process is repeated at other individual setups until multiple/all bends on the part are bent. The ability to process multiple bends using different replaceable radius tip punches, moving from individual setup to individual setup is what makes the replaceable radius tip punches is the key feature of the present invention.

For of various different size replacement radius tip punches, the shape of the punch allows for the common shut height. The geometry of the punch chip is designed with a solid straight portion of the profile above the bending radius of the punch chip. This solid straight area of the chip allows for height adjustment at time of manufacturing based on differing chip radii and angles for each punch chip.

FIGS. 4A and 4B illustrate the multiple punch tools that can be installed in the press brake apparatus to enable multiple bends to be formed on a part. Alternately, multiple bends can be formed on a part using a single tool set-up. In particular, the first bend is formed by the punch chip indicated at 4-1; the second bend is formed by the punch chip indicated at 4-2; the third bend is formed by the punch chip indicated at 4-3; and the fourth bend is formed by the punch chip indicated at 4-4.

Note that Figure A is a partial front view of the press brake of the present invention illustrating a multiple tool arrangement and FIG. 4B is a side view of the press brake shown in FIG. 4A illustrating different tools 50, 52, 54 and 56 with common shut heights represented by reference letters C and D.

FIG. 4B shows in more detail how a hook shaped portion 60 of the press brake system engages notched shape portion 33 of punch holder 22 such that the shut heights C and D are substantially identical and thus provide the novel features of the invention as noted hereinabove.

While the invention has been described with reference to its preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the true spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its essential teachings. 

What is claimed is:
 1. A press brake system using a first punch tool for bending a workpiece, the workpiece requiring several bends with different radii, said first punch tool comprising: a punch holder having an upper portion of a first shape; a first punch tip having a first radius formed on the lower portion of said punch holder; and means for removably securing said first punch tip to said punch holder.
 2. The press brake system of claim 1 wherein said first punch tip is removed from said punch holder and replaced by a second punch tip having a second radius, said first radius being different from said second radius.
 3. The press brake system of claim 1 further including a second punch tool, said first and second punch tools extending along a longitudinal axis of said press brake system, each of said second tools having an upper portion of a shape substantially identical to said first shape.
 4. The press brake system of claim 3 wherein said first and second punch tools have punch tips of a different radii.
 5. The punch brake system of claim 4 wherein the shut height of said first and second punch tools are substantially the same.
 6. A punch tool for use in a brake press system, said punch tool having upper and lower portions comprising: a punch holder extending along a horizontal axis, said upper portion of said punch holder having a notch adapted to be engaged by a component within said press brake system; and a punch tip that is removably secured to said lower portion of said punch holder.
 7. The punch tool of claim 6 wherein said punch tip is secured to said punch holder by a plurality of fasteners extending along said horizontal axis. 